Friction hinges are the usual means for connecting the lid and the base unit of laptop computers. Until recently, heat dissipation from the circuitry within laptops has been successfully managed within the base unit that ordinarily contains most of the heat generating components, principally the CPU itself. The recent use in laptops of faster processors that generate more heat requires the development of more efficient heat dissipation strategies.
The lid of a laptop, which contains the screen, has a large surface area that forms the cover. Since this outside cover surface is more or less vertically orientated while the laptop is in use, it can advantageously be used for heat dissipation. However, since the CPU is in the base, it becomes necessary to find an efficient means for transporting the heat from the base into the lid.
Heat pipes are the preferred method for moving heat efficiently. A heat pipe is, typically, a sealed copper tube containing a fluid-gas mixture. Since such a tube cannot withstand repeated bending, a single heat pipe cannot be used to connect the heat source in the base to the heat dissipation structure in the lid. Therefore, separate heat pipes are used in the base and in the lid, and a rotary joint is needed that forms a good thermal connection between them. Combining a friction hinge with a rotary thermal joint saves space and weight, both of which are scarce in laptops, and the cost can also be reduced by this combination.
The actual mounting of the lid assembly to the base assembly during manufacture of a laptop can be quite complex, involving the mechanical connection as well as the routing of a number of electrical conductors. Laptop manufacturers have asked for a thermally conductive friction hinge with subassemblies that can be mounted to the base and the lid and easily joined during the final assembly of the laptop with a minimum of loose components to be handled during that joining. Our invention provides such a thermally conductive friction hinge.
It is an object of our invention to provide a small friction hinge that requires a constant torque to rotate one side of the hinge with respect to the other, and which has high thermal conductivity between the sides of the hinge.
It is a further object of the invention to provide a thermally conductive friction hinge whose two sides can be individually preassembled into two units that can then easily be joined in a final assembly.
It is another object of our invention to provide a thermally conductive friction hinge that is separable into two subassemblies having no thermal boundary therebetween.
An additional object of our invention is to provide a friction hinge having high thermal conductivity whose two preassembled sides can be easily aligned during the final assembly operation.
An additional object of our invention is to provide a friction hinge having high thermal conductivity whose two preassembled sides can be easily joined in final assembly.
Still other objects and advantages of the invention will, in part, be obvious and, in part, be apparent from the following description.